Fases de un proyecto de Simulación 36

Figure 14 shows our preferred history of assembly and breakup of the Yangtze and Cathaysia blocks with other continental fragments prior to their amalgamation in the

Neoproterozoic to form the South China Craton. In the mid-Paleozoic, South China rifted off northern Gondwana, drifting across the Tethys Ocean to collide with North China in the late Paleozoic to Mesozoic to form part of the Asian segment of Pangea.

The Archean record of the Yangtze Block indicates a period of Neoarchean

continental lithospheric development and stabilization. The record is restricted spatially to isolated fragments, such as the Kongling complex, and their link to other Archean cratons is unknown. Late Archean and Paleoproterozoic magmatic and metamorphic events in the Yangtze in the period 2.9 Ga to 1.8 Ga are similar to in character to those in northwest Laurentia (Fig. 12) suggesting a common record of lithospheric formation culminating in accretion of the cratonic masses, and perhaps also involving Siberia, which show a similar tectonothermal record and suggest a spatial association (Wang et al., 2016a). Northern Laurentia and the Yangtze Block display a similar subsequent record of 1.8-1.6 Ga sedimentation and magmatism associated with lithospheric extension and continental

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breakup, which is taken to indicate separation of the two continental fragments. Younger Mesoproterozoic successions are largely absent from the Yangtze Block (Figs. 3, 12).

No Archean rocks are exposed in Cathaysia but their presence has been inferred on the basis of Archean Nd and Hf model ages and inherited zircons in Paleoproterozoic granites (Liu et al., 2014, and references therein). The composition of the granites changes from an earlier pulse of I- and S-types emplaced between ca. 1929-1875 Ma and interpreted to relate to a continental collisional environment, and later ca. 1880-1850 Ma A-types, along with minor mafic magmatism as young as 1760 Ma (Li et al., 2010) related to a post-collision collapse and extensional setting (Liu et al., 2014; Yu et al., 2009). The granites were emplaced into the Badu Complex which underwent high-grade granulite facies metamorphism around 1890 Ma (Yu et al., 2012). The record of Paleoproterozoic

tectonothermal events in Cathaysia and ages of detrital zircons correlates well with events in northern India (Figs. 12, 13), suggesting that the two were linked. Thus, the record of

metamorphism and granite magmatism in Cathaysia is taken to record its assembly with northern India around 1910-1875 Ma as part of the more general assembly of the Nuna supercontinent (Figs. 4, 12). The paleogeographic relations of Cathaysia prior to this time are unknown.

Assembly of the Yangtze and Cathaysia blocks occurred along the Jiangnan Orogen in the early Neoproterozoic (Figs. 3, 4, 10). Geochemical affinities of rock units within the orogen suggest formation in an overall supra-subductions zone environment (Fig. 9), which extended from ca 1000-810 Ma. An overall subduction-related accretionary orogen setting continued until almost 700 Ma along the western margin of the Yangtze and along strike equivalent belts in the Seychelles, northern Madagascar and northwestern India (Fig. 11). This protracted record of convergent plate margin activity establishes that the assembly of the Yangtze and Cathaysia blocks occurred on the margin of an already assembled Rodinia

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supercontinent (Fig. 4), or possibly on a tectonic plate separate from Rodinia (Merdith et al., in press). Bi-modal magmatism that overlaps in age with this period of convergent plate margin activity likely reflects lithospheric extension within backarc basin settings. The united South China Craton remained fixed to northern India during Rodinia breakup and Gondwana assembly from the mid-Neoproterozoic to early Paleozoic (Fig. 4). The final assembly of Gondwana took place in the early Paleozoic along the Kuunga orogen and resulted in

amalgamation of the Sanya Block in southern Hainan Island, which at that time lay along the northwestern margin of Western Australia, with the rest of South China and India (Fig. 6). Breakup of South China from northern Gondwana commenced in the mid-Paleozoic coincident with the assembly of Pangea (Figs. 4, 14).

In summary, South China and its constituent lithotectonic fragments record a long history of assembly and dispersal within the major supercontinents of Earth history (Figs. 4, 14). The late Archean timing of crustal growth and reworking events in South China correspond with a period of widespread craton formation (Bleeker, 2003). This phase of continental growth has been termed the Kenor supercontinent or supercraton but it is unclear to which, if any, of the other temporally equivalent cratons that the various Late Archean elements in South China were linked. Assembly of Yangtze with Laurentia and Cathaysia with India were part of a series of events associated with the formation of the late

Paleoproterozoic supercontinent of Nuna. The breakup of Yangtze and Laurentia corresponds with the partial breakup of Nuna but the core elements of Laurentia, Siberia and Baltica appear to have remained largely intact through the Mesoproterozoic (Cawood and

Hawkesworth, 2014; Cawood et al., 2016; Evans and Mitchell, 2011; Pisarevsky et al., 2014) and Cathaysia remained attached to India throughout this timeframe (Yu et al., 2012)

positioned along, or outboard of, the margin of the assembling Rodinia supercontinent. The position of the Yangtze Block after it separated from Laurentia for the remainder of the

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Mesoproterozoic prior to assembly with Cathaysia is unknown. Limited paleomagnetic and geological evidence suggests that the combined India and Cathaysia broke away from

southern Baltica in the late Mesoproterozoic (Pisarevsky et al., 2014, and references therein). The Yangtze Block was sutured to Cathaysia along the Jiangnan Orogen in the early

Neoproterozoic, creating the combined South China Craton (Cawood et al., 2013; Zhao, 2015). Subduction continued along the western margin of the Yangtze until the mid- Neoproterozoic and extended through northwestern India to the Seychelles and northern Madagascar (Ashwal et al., 2013; Zhou et al., 2006). During Gondwana assembly India- Cathaysia collided with the Western Australia-Mawson block along the Kuunga orogen resulting in the accretion of the Sanya Block to the rest of South China (Xu et al., 2014b). The accretion of Laurussia to Gondwana in the mid-Paleozoic to form Pangea corresponded with lithospheric extension along the northern margin of Gondwana and the separation of a number of continental blocks including South China, which then drifted northward across the Paleo-Tethys to collide with the Asian segment of Pangea in the Permo-Triassic (Metcalfe, 2013).

Acknowledgements

This paper is financially supported by a NSFC Major Program (41190070) entitled “Reconstruction of East Asian Blocks in Pangea”. PAC acknowledges support from the Australian Research Council grant FL160100168 and WW thanks the support from

“Thousand Youth Talents Plan”. We thank Di-Cheng Zhu, Qing Wang and Gong Jian Tang for help with drafting of figure 1. We have benefited from discussions over many years with Min Sun. The manuscript benefited from insightful reviews by Alan Collins and Liangshu Shu.

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8. Figures

Figure 1. Tectonic map of Asia showing continental blocks and bounding sutures (adapted from Li, 2006; Metcalfe, 2013).

Figure 2. Geological map of South China. Uncolored areas depict Phanerozoic sedimentary and igneous rocks.

Figure 3. Time space plot showing age range of principal rock units and tectonothermal events within the South China Craton. Emieshan Large Igneous Province, dated at 260 Ma (Huang et al., 2016), and which overlies part of the southwestern Yangtze Province, is not shown. Abbreviations: BB – Baoban Group and equivalents; BG – Banxi Group and equivalents; BJ – Bikou and Julin groups and equivalents, and associated plutonic complexes; BS – Badu supracrustals; DG – Dongchuan Group; DP – Datangpo Formation; DS – Dahongshan Group; GC – Gucheng Formation; HC – Houhe Complex; HK – Hekou Group; HS – Huangling intrusive suite; JK – Jiangkou Formation; KC – Kongling Complex and equivalents; KY – Kunyang & Yanbian group and equivalents; LG – Longquan Group and equivalents along with associated intrusive rocks; LS – Lengjiaxi Group; NT – Nantuo Formation; QG – Quanyitang granite; SS – Sizhoushan Formation; SG – Shuangxiwu Group; LJG – Lengjiaxi Group and equivalents; SY – Shenshan and Yunkau groups and

equivalents; TD – Tianzidong Formation; XM – Xiangmeng Formation; YG – Yunkai Group and equivalents; ZL – Zhengyuanling Formation.

Figure 4. Schematic paleogeographic reconstructions showing position of the Cathaysia, Yangtze blocks in various inferred supercontent reconstructions at: a) Nuna assembly at ca. 1.7 Ga (adapted from Pisarevsky et al., 2014); b) Nuna at 1.35 Ga (adapted from Pisarevsky et al., 2014); c) Rodinia assembly at ca. 900 Ma (adapted from Cawood et al., 2013); d) Gondwana assembly at 500-450 Ma (adapted from Cawood and Buchan, 2007); e) Pangea assembly at ca. 300 Ma (adapted from Metcalfe, 2013).

Abbreviations: Am, Amazon; Aus, Australia; Co, Congo; Ba, Baltica; In, India; La – Laurentia; NC, North China; Ma, Mawson; WAf, west Africa; SF, San Francisco; Si, Siberia; Y: Yangtze Block, CA: Cathaysia Block, Mad: Madagascar; , IC: Indo-China Block.

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Figure 5. Detrital zircon age distributions for Neoproterozoic and Phanerozoic sedimentary rocks from: a) the Ordovician strata above the unconformity in the Sanya region, Hainan Island (Xu et al., 2014b), b) the Cambrian strata below the unconformity in the Sanya region, Hainan Island (Xu et al., 2014b), c) Early Paleozoic strata in South China (Chen et al., in press; Wang et al., 2010c; Xu et al., 2013; Xu et al., 2014a), d) Tethyan Himalaya (Hughes et al., 2011; Myrow et al., 2010; Myrow et al., 2009), e) Ordovician, Permian and Triassic strata, Western Australia (Cawood and Nemchin, 2000; Kettanah, 2015; Veevers et al., 2006), f) Northampton Complex, Western Australia (Ksienzyk et al., 2012), g) Late Neoproterozoic strata, Cathaysia Block, South China Craton (Yu et al., 2008; Yu et al., 2010); h) Precambrian quartzite in the Qiongzhong Block, Hainan Island (Li et al., 2008b). Age ranges important in

comparing data sets between the regions are highlighted in blue (1300-1100 Ma) and orange (1000-900 Ma) color bands; n—total number of analyses. All data based on analyses with <10% discordance. Ages older than 1000 Ma were calculated using

207_Pb/206_{Pb ratios, and ages younger than 1000 Ma were calculated using} 206_Pb/238_U

ratios. Data used in plots given in Supplementary Table 1.

Figure 6. a) Simplified reconstruction showing the location of the South China Craton and other Asian continental blocks along the northern Gondwana margin at around 500 Ma (adapted from Xu et al., 2014b). The position of South China outboard of India is based on similarities of the detrital zircon record of the two regions (see figure 4). However, the Sanya Block from Hainan Island is detached from the rest of South China and placed close to Western Australia on the basis of the Cambrian provenance and faunal record. By the Ordovician the Sanya Block was joined to the rest of the South China Craton (see figure 5), and the region then became part of an accretionary orogen on the northern margin of Gondwana (Cawood et al., 2007); b) and c)

Schematic cross-sections from India-South China to Australia for the Cambrian and Ordovician showing inferred suturing of Sanya Block with the rest of South China along the Kuunga suture.

Figure 7. Detrital zircon age distributions for Cryogenian rocks from: a) Southeastern

Australia; b) western Laurentia; c) Lesser Himalaya of northwest India; and d) South China. Data compiled from Dehler et al. (2010) for The Unita Mountain Group and Big Cottonwood Formation, Laurentia; Gehrels et al. (1996) and Ireland et al. (1998)

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for Adelaide Geosyncline, East Australia; Wang et al. (2012d) and Wang and Zhou (2012) for the Nanhua sequences of South China; and Hofmann et al. (2011) and McKenzie et al. (2011) for the Lesser Himalaya strata. Data used in plots given in Supplementary Table 2.

Figure 8. Initial εNd(t) value versus selected trace element diagrams for the Cryogenian

(Nanhua, ~810-720 Ma) sedimentary rocks from the Yangtze Block of South China. Neoproterozoic felsic and mafic igneous rocks from South China and southeastern Australia are presented as potential sedimentary sources. Data sources: Nanhua Basin sequences (Wang et al., 2012d; Wang et al., 2011); 830-800 Ma mafic rocks from southern Australia Gardner Dyke Swarm and equivalent units (Wang et al., 2010b; Zhao et al., 1994); 820-760 mafic igneous rocks from South China (Li et al., 2002a; Lin et al., 2007; Ling et al., 2003; Wang et al., 2008a; Zhou et al., 2007); and 830-810 Ma granitic rocks from South China (Li et al., 2003a). Data used in plots listed in Supplementary Table 3.

Figure 9. Hf-Th-Ta diagram (after Wood, 1980) for Neoproterozoic igneous rocks from the Jiangnan, Panxi-Hannan and Cathaysia domains of the South China Craton. Sources of data, Jiangnan domain: Chen et al. (2014b), Li et al. (2008a; 2009), Wang et al. (2014a), Wang et al. (2008b; 2004), Yao et al. (2016a; 2016b; 2014a; 2015; 2014b), Ye et al. (2007), Zhang et al. (2013a), Zhang et al. (2012b), Zhang and Wang (2016), Zhang et al. (2012d; 2013b), and Zhao and Zhou (2013); Panxi-Hanna domain: Cai et al. (2014; 2015), Dong et al. (2011), Du et al. (2014), Li et al. (2002a), Ling et al. (2003), Wang et al. (2016c), and Zhou et al. (2006; 2002); Cathaysia domain: Li et al. (2005), Shu et al. (2011; 2008b), Wang et al. (2013b) and Zhang et al. (2012a). Data used in compiling diagram listed in Supplementary Data Table 4.

Figure 10. Diagram depicting distribution and direction of inferred convergent plate

boundaries within and around the South China Craton. See text for discussion of data. Figure 11. Proposed tectonic setting and paleogeographic links between Neoproterozoic

Panxi-Hannan Belt in South China with time equivalent igneous activity in northwest India, Seychelles and Madagascar (Ashwal et al., 2013; Zhou et al., 2006). Extension in the upper plate of the convergent plate margin setting basin formation and

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Figure 12. Time - space plot for principal early Paleoproterozoic to early Mesoproterozoic tectonothermal events within the northwestern Laurentia, Siberia South China and NW India. The tectnothermal events of Rae Craton include the Buffalo Head terrane and the Taltson - Thelon tectonic zone, which were accreted to or collided with the Rae Craton. The Wopmay orogen includes Coronation margin, Great Bear magmatic zone, Hottah terrane and Fort Simpson terrane. Abbreviations: AV - Aravalli

Supergroup; BBS - Big Bear sequence; BBG - Baoban Group; BD - Badu complex; BG: Baker lake Group; DA: Damtha Group; DE: Deoban Group; HB - Hornby Bay Group; JU - Jutogh Group; L.AMs - Lower Amer Group and its equivalents

including the Lower Murmac Bay, Ketyet River and Thluicho Lake groups; LD - Lower Dongchuan Group; LP - Lookout Point Formation; MK - Mukun Group; NDL - North Delhi Supergroup; PZ - Pitz Formation; RA - Rampur Formation; RO - Racklan Orogeny; SDL: South Delhi Supergroup; SL - Shilu Group; SQ - Sin Quyen Group; TD - Tangdan Group; TL - Thelon Formation; U.AMs - Upper Amer Group and its equvialents: the upper Murmac Bay, Ketyet River and Thluicho Lake groups; UD - Upper Dongchuan Group; UG - Uchur Group; WE - Wernecke Supergroup; WG - Whart Group. Data sources used in compilation of this diagram listed in Supplementary Figure 1.

Figure 13. U–Pb age spectra of zircons from Proterozoic metasedimentary rocks of: a) northern Aravalli orogen (Kaur et al., 2011; Wang et al., 2017); b) eastern Cathaysia Block, South China (Yu et al., 2012); c) Madagascar (Bauer et al., 2011; De Waele et al., 2011); d) inner Lesser Himalaya (Long et al., 2011; Martin et al., 2011; McKenzie et al., 2011; McQuarrie et al., 2008; Parrish and Hodges, 1996; Richards et al., 2005); e) southwestern Yangtze Block (Wang et al., 2012a; Wang and Zhou, 2014; Zhao et al., 2010); f) northwestern Laurentia (Rainbird and Davis, 2007); and g) northern margin of North China Craton (Ma et al., 2014; Zhong et al., 2015). Data used in compiling diagram listed in Supplementary Data Table 5.

Figure 14. Diagram highlighted principal craton blocks that South China and its constituent Yangtze and Cathaysia blocks have been associated with since the Archean and their relationship to supercontinent cycles. Blue lines connecting blocks represent inferred time range of continental rifting and drift, whereas red lines represent duration of convergence. Abbreviations: Cath – Cathaysia; GW – Gondwana; Pa – Pangea; La – Laurentia; Rodin – Rodinia; SC – South China; Sth – South; Yz – Yangtze.

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